Regulated d. c. power supply



Dec. 10, 1957 D. s. SCORGIE 2,816,260

REGULATED D. C. POWER SUPPLY Filed July 31, 1956 INVENTOR DONALD G. SCORGIE I v BY ATTORNEYS United States Patent I 2,816,250. REGULATED'D. C.P WER SUPPLY DiirraluGgjScoii Pittsburgh, P51, assignor o the United States (if America asrepresented by the Secretary of the Navy a uea'iifiii'nu si,1e56, sefial'No. 601,330

9"Claims. Cl. 321-18) (Granted under Tine-s; U."Si'Code" 1 952 sec; 266)- The invention; described herein may; be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any-royalties thereon or therefor.

This invention relates to voltage regulated rectifiers and more particularly to rectifiers employing magnetic amplifier'circuits and the Zener breakdown characteristic of a silicon-junction diode. In this invention the regulated D..-C. voltage isproduced from non-electronic components. The voltage reference is the Zener breakdown voltage of a crystal rectifier such as a silicon-junction diode, when such voltage is applied to the diodein a polarity reverse to thatof the normal polarity of the voltage application to the diode.

With s'ilicon-junctiondiodes the Zener breakdown voltage can be established in a range from about 5 to 20 volts. By applying a silicon-junction diode in the control winding of a reset type magnetic amplifier circuit, voltage regulation is achieved;

An object of this invention is to provide a voltage regulator producing a constant D.-C. voltage.

Another object of this invention is to provide avoltage regulator. employingonly magnetic components; I,

Another object of this invention is to provide a D.-C. voltage regulator'using a Zener breakdown voltage as a reference level.

Another object of this invention' is to provide a voltage regulatoremployinga reset type magnetic amplifier ci rcuit in which a silicon-junction diode is used in the control winding.

A further object of this invention is to provide a magnetic amplifier circuit for unidirectional voltage regulation.

Other objects and many of the attendant advantages of this invention will be readily appreciated at 'the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawing in which like reference numerals designate like parts throughout the figures thereof and wherein:

Fig. 1 illustrates the circuit of a preferred embodiment ofthis invention. 7

Fig. 2 of the drawing illustrates an embodiment of the invention in which a variable tap is provided for connecting the control circuit to the output circuit.

Fig. 3 illustrates the Zener breakdown characteristic curve of a silicon-junction diode as used in this invention.

In'the reset. type magnetic circuit as used in this invention, the cycle of operation is the complete cycle of an alternating voltage source, for example, a positive and a negative half-cycle of such source. Reset magnetic amplifiers include saturable cores, a control winding and a load winding on each core and control circuits and load circuits for each winding. The control circuits and load circuits are equipped with unidirectional current flow means poled so 'that 'for a given core, the current flows in the load circuit on one half-cycle, for example, the positive half-cycle, and current flows through the control cir cuit on the other half-cycle, for example, the negative half-cycle. The current flow through the load winding will drive the core to saturation and the current flow magnetize the core.

2,816,260 u P-atented Dec. 10,

2r, through the control winding will c'ause the' core to" deviate from saturation. The degree" of' desaturation" accomplished during. the control orresethalf cycle'depends upon the fbucking potential the control circuit; v

The response time for" the" reset magnetic amplifier is one lralf cycle. Duringa'firsthalf-cycl, the'voltage is first applied to the" loadwinding. As'soon as the'core becomes saturated or fried theloa'd winding appears as a" short circuit andthe voltage applied to the load circuit appears across th'e'load: Since high reman'ence cores are used, the'sa'tura'tio'n level' established by theload winding will remainuntiFthe control circuit demagnetizing currentflows. Duringth'e' control or reset halficycle, voltage will be applied toth'e core in a direction tod'e i The extent 'ofdernag'netization'm'ay dependupon'the m'agnitudeof abuckingpotential source; The degree of demagnetizationeffected will vary. from zei'o'demagnetizatiorr whenthfebucking potential'is equal to are alternating voltageapplieddn' thecontrol circuit, to complete demagnetization w'he'n'theb'ucking potential is zero. Themagnetization" level of'tlie core thus determined'by the control ciicuitwill .affectthe length of.'time that the'alternating' voltage applied in" the load circuit appearsa't' the load resistor. If the demagnetization by the control circuit 'were complete in a half-cycle previous to a particular load half-cycle','.the applied alternating voltage will appear across theloadwi'ndingfor a large portion of the load half-cycle a'ridthe' applied voltage will appearacross the loadfor asrnall portion of the load half-cycle; Hence the resulting outpu'tffrom the mag? netic amplifier will be relatively small. If, on the other hand the demagnetization by the control circuit was zero in a half-cycle previous to -a particular l'o'a'd. half-cycle, then the appliedalternating voltage source will appear across the load for the entire load half-cycle and the output from the magnetic amplifier thus is relatively large.

In thepresent invention the reset magnetic circuit is employed in conjunction with a silicon-junction diode to produce a voltage regulation device. The control windirigs of saturab'le cores are part 'of a circuit in which a voltage is applied acros a silicon-junction diode in the reverse polarity. When the voltage applied to the diode exceeds the Zener breakdown voltage, current will flow in the circuit including the control windings of the saturable core. Such current flow in the windings willreduce the magnetization level of the core to effect a change in the time integral of the output voltage in the load circuit. The load resistor for the magnetic cores is also the output for the regulated voltage.

Referring now to Fig. l of the drawings in which a voltage regulator circuit employing a reset type magnetic amplifier-is shown, saturable cores 11 and 13 each have a load winding, a control winding, and a bias winding. Core 11 has load'windin g 15, control winding 17, and bias winding 19, and core 13 hasload winding 21, control winding 23, and bias winding-25. A load circuit includes in part, serially connected load windings 15 and 21 in series with inductor 29 load resistor 31 and rectifier 33. A line or supply voltage, E connects between the load winding 15 and 21 at terminal 35 and between rectifiers 39 and 41 at terminal 3'] The other terminal of rectifier 39 connects between rectifier 27 and inductor 29. One terminal of rectifier '41 connects between rectifier 33 and one terminal of load resistance 31. Capacitor 43 connects in parallel to the load resistance 31. Inductance 29 and capacitor 43 form a filter forthe rectifier output. The control circuit comprises a series circuit containingserially connected control windings 17' and 23 in series 'With siliconjunction diode '45, a'ndloa'd resistor 31. A bias circuit includes serially connected windings I9 and '25 in series with "resistor 49 and rectifier b'ridge Que 'end ofYresismi- 49 connects to juncture 53 of the rectifier bridge 51 and one end of winding 25 connects to juncture 55 of rectifier bridge 51. An alternating voltage is supplied to terminals 57 and 59 and a direct voltage appears at junctures 53 and 55 to supply a direct magnetizing voltage to cores 11 and 13. Resistor 49 limits the current flow through the bias windings.

The dots on the end of core windings indicate the polarity or winding sense. For example, a core having windings with dots at the same end will be magnetized in the same sense in response to voltages of the same polarity applied to each winding. The dots at one end of the winding indicate a winding sense such that it a particular polarity voltage is applied, the core will be magnetized in a particular direction and if the dot is at the other end, with the same polarity of voltage applied, the core will be magnetized in the opposite direction. The relationship of the voltage polarity t the direction of magnetization as shown by the dots in Fig. 1 is consistent throughout the drawing. The winding sense as indicated by the dots is the same for all the windings in cores 11 and 13.

In Fig. 3 of the drawings the approximate relationship of the applied voltage to the current flow for a siliconjunction diode is illustrated. +E indicates a voltage polarity for normal operation and E indicates a voltage of reverse polarity applied to the silicon-junction diode in which the reverse direction current flow is plotted as +1 and 1 along the ordinate. Curve indicates approximately the relationship between voltage applied to the rectifier and the resultant flow. As the positive voltage increases, the current flow increases. When voltage is applied in the opposite polarity or E direction, the current flow is extremely small increasing slightly until the voltage E or the Zener breakdown voltage is reached. When the breakdown voltage is reached, the current flow will increase sharply.

In operation, an alternating voltage is applied to terminals 35 and 37. On the positive half-cycle, that is for example, when terminal 35 is positive and terminal 37 is negative, the current flow path is through rectifier 41, load resistor 31, inductor 29, rectifier 27, load winding on core 11. In the initial portion of this half-cycle, core 15 will be unsaturated and the winding impedance will be high until the core becomes saturated. The greatest part of the applied voltage during the time interval that the core is unsaturated will appear across winding 15. As soon as core 11 becomes saturated, the greatest part of voltage E applied at terminals 35 and 37 will appear across load resistor 31.

As pointed out earlier, the time portion of the halfcycle in which the applied voltage E appears across load resistor 31 depends upon the state or level of saturation of the core at the beginning of the halt-cycle which in turn depends on the degree of demagnetization accomplished by the control circuit in the previous half-cycle.

Consider now the control circuit including the siliconjunction diode 45 and control windings 17 and 23 with respect to the rectifier operation. Viewing saturable cores 11 and 13 as parts of a magnetic amplifier circuit, core 11 is 180 out of phase with core 13. A saturating voltage is applied to core 11 during the half-cycle in which there is current flow through winding 15 and core 13 is saturated during the other half-cycle in which there is a current flow through winding 21. The silicon-junction diode 45 is poled for current flow from the positive terminal 3%) through diode 45 through winding 17 and Winding 23 and then to negative terminal 32. When the potential across silicon-junction diode 45 in reverse polarity exceeds the Zener breakdown voltage, current will flow in the control circuit in the direction of the reverse polarity. it the breakdown voltage is exceeded during the first halicycle or the halt-cycle in which current is flowing through winding 15 and since the current flow through winding 17 is of the opposite direction of that through winding 15, the resulting current flow through winding 17 tends to reduce the saturation level of core 11. On the second 4}. half-cycle of operation, current flows through winding 21 until core 13 reaches the saturation level. At this point the E will be applied to terminals 31) and 32. How ever, since on the previous half-cycle the control current through winding 23 has partially or fully desaturated or reset core 13, the output voltage will be applied to terminals 30 and 32 for a shorter period of time, and hence the effective D. C. level of the output voltage is reduced. Should the output voltage level during the second halfcycle create a voltage drop across silicon-junction diode 45 greater than the reverse breakdown potential, current will again flow through the control windings 17 and 23 at the beginning of the second half-cycle, core 11 is at a particular saturation level as set by the previous halfcycle. Current flow through winding 17 will partially or totally desaturate or partially saturate in the reverse sense core 11 such that in the succeeding half-cycle of operation a greater portion of the applied alternating voltage Will be used to saturate core 11. This will reduce the time portion of the half-cycle of the voltage appearing at the output terminals and hence the D. C. level Will be reduced.

The voltage appearing at the load terminals acts as a source voltage for the control circuit. When the voltage E at the load is less than E or the Zener breakdown voltage there will be no current flow in the control circuit and voltage E will appear across the silicon-junction diode 45. Whenever E becomes greater than E the diode 45 breaks down and the voltage applied will be divided among control windings 17, 23 and the diode 45. Diode 4-5 now becomes a low resistance and the voltage E is divided largely between control windings 17 and 23. The voltage across the control winding will act to demagnetize the core going through its reset half-cycle. For example at the beginning of the negative half-cycle core 11 will be saturated from the previous positive half-cycle. If the voltage E becomes greater than E during this negative half-cycle, the current will flow through the control circuit and demagnetizing energy from control winding 17 will be applied to core 11.

The extent of demagnetization of core 11 will depend upon the magnitude of the voltage in the control circuit and hence the magnitude of the voltage applied to the load terminals. The higher the output voltage, the greater the voltage across the control Winding and greater amount of demagnetization results. On the second positive half cycle the output voltage will depend upon the magnetization level of core 11 at the beginning of the cycle. If core 11 has been demagnetized a great amount, then the output voltage on the second half cycle Will be low. if the core has not been demagnetized or demagnetized a small amount then the output voltage during the second positive half cycle will be high. Thus a control of the output voltage is effected.

In the explanation of the operation, only core 11 was discussed. However, the operation of core 13 is identical although it will operate on alternate half cycles. That is, when core 11 is experiencing the load half cycle, core 13 will be experiencing the control halt cycle. With such arrangement, full wave voltage regulation is achieved.

To further regulate the magnitude of the output voltage, bias windin gs 19 and 25 may be supplied with demagnetizing voltage from rectifier circuit 51. If an alternating voltage is applied to terminals 57 and 59, a direct demagnetizing current will flow through windings 1.9 and 25. This current will be small compared to the currents flowing in the load and control circuits. With such demagnetizing bias windings, the output voltage may be reduced. With this demagnetizing efiect applied to the cores, less regulation by the control circuit will be necessary. The amount of demagnetization desired by the bias winding may be controlled by changing the size of the current limiting resistor 49.

in the load circu t, inductor 2% and capacitor E3 or a filter circuit to reduce the ripple voltage at the output terminals.

Referring now to Fig. 2 illustrating an embodiment of the invention in which a variable tap is provided, resistor 131 has tap 105 connecting the control circuit to the output circuit. By moving tap 105 along resistor 131 variable amounts of voltage can be applied to the control circuit with the tap positioned at the positive end of load resistor 131, the full output voltage of the regulator will be applied to the control circuit. With the tap positioned at any other place the voltage applied to the control circuit will be less than the output voltage of the regulator. With a variable tap on the control circuit, it is possible to operate the regulator with an output voltage larger than the Zener breakdown voltage of the silicon-junction diode.

Capacitor 47 is added to filter any pulses from the rectifier voltage reference.

Since the width of the hysteresis loop will vary with the frequency of the applied voltage, current limiting resistor 49 will be varied accordingly. For the particular frequency of operation, resistor 49 should be sized so that the current in the load circuit will remain approximately constant at fixed ambient temperatures. Siliconjunction diodes with either positive, zero or negative coefiicients may be used, however since the cores may require a change in magnetizing current with a change in ambient temperature, a diode with a negative temperature coefiicient may be advantageous.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

I claim:

1. A voltage regulator comprising a full wave magnetic amplifier having two cores saturated alternately upon successive half cycles of an alternating voltage, a series control circuit comprising two control windings and a diode connected across the amplifier output, said diode poled such that current flow will occur when the Zener breakdown voltage is exceeded across said diode.

2. A voltage regulator comprising a full wave reset magnetic amplifier, a control circuit including control windings and a silicon junction diode connected across the amplifier output, said diode poled reverse to the current flow polarity of the amplifier output voltage.

3. A voltage regulator comprising a pair of saturable cores, a control winding, a load winding on each of said cores, 2. load circuit including a load impedance serially connected to said load windings, an alternating voltage source, a plurality of unilateral impedance means connecting said source and said load winding, said impedance means poled to provide a magnetizing voltage across a first one of said load windings during the odd half cycles of said source and across a second one of said load windings during the even half cycles of said source, a control circuit including said control windings and a silicon junction diode serially connected to said load impedance, said diode connected such that a demagnetizing voltage will appear across said control windings when the voltage across said diode exceeds the breakdown voltage of said diode.

4. A voltage regulator comprising a pair of saturable cores, a control winding a bias winding and a load winding on each of said cores, a load circuit including a load impedance serially connected to said load windings, an alternating voltage source, a plurality of unilateral impedance means connecting said source and said load windings, said impedance means poled to provide a magnetizing voltage across a first one of said load windings during the odd half cycles of said source and across a second one of said load windings during the even half cycles of said source, a control circuit including said control windings and a silicon junction diode serially connected to said load impedance, said diode connected such that a demagnetizing voltage will appear across said control windings when the voltage across said diode exceeds the breakdown voltage of said diode, a bias circuit comprising said bias windings serially connected, a unidirectional voltage source connected to said bias windings poled to partially demagnetize said cores.

5. A voltage regulated rectifier comprising, a full wave reset type magnetic rectifier having two saturable cores, a load winding on each of said cores, a control winding on each of said cores, a pair of direct current output terminals, a load resistor between said terminals, an alternating supply voltage; a first load circuit including said load winding of said first core, rectifier means, said alternating voltage and said output terminals to provide a D. C. voltage output across terminals during the firing half cycle of said first core; a second load circuit including said load winding of said second core, rectifier means, said alternating voltage and said output terminals to provide a D. C. voltage output across said terminals during the firing half cycle of said second core; a control circuit including said control windings and a silicon junction diode crystal connected to said output terminals, said diode operative to breakdown and cause current flow through the control windings to desaturate the core that is on its reset half cycle.

6. A voltage regulator comprising a pair of saturable cores, a control winding and a load winding on each of said cores, a load circuit including a load resistor having a variable tap serially connected to said load windings, an alternating voltage source, a plurality of unilateral impedance means connecting said source and said load windings, said impedance means poled to provide a magnetizing voltage across a first one of said load windings during the odd half cycles of said source and across a second one of said load windings during the even half cycles of said source, a control circuit including said control windings and a silicon junction diode serially connected to the variable tap and one terminal of said load resistor, said diode connected such that a demagnetizing voltage will appear across said control windings when the voltage across said diode exceeds the breakdown voltage of said diode.

7. A voltage regulator comprising a full wave magnetic amplifier having two cores saturated alternately upon successive half cycles of an alternating voltage, a bias winding and a series control circuit comprising two control windings and a diode serially connected to the amplifier output, said diode poled such that current flow will occur when the Zener breakdown voltage is exceeded across said diode, a bias circuit comprising said bias windings serially connected, a unidirectional voltage source connected to said bias windings poled to partially demagnetize said cores.

8. A voltage regulator comprising a full wave reset magnetic amplifier, a bias winding and a control circuit including control windings and a silicon junction diode serially connected to the amplfier output, said diode poled reverse to the current flow polarity of the amplifier output voltage, a bias circuit comprising said bias windings serially connected, a unidirectional voltage source connected to said bias windings poled to partially demagnetize said cores.

9. A voltage regulator as set forth in claim 8 including 2-. capacitor connected in parallel with said silicon junction diode.

References Cited in the file of this patent UNITED STATES PATENTS 2,100,715 Jenks Nov. 30, 1937 2,403,891 Lamm July 9, 1946 2,525,451 Graves Oct. 10, 1950 2,721,303 Silver Oct. 18, 1955 2,753,510 Smith July 3, 1956 2,770,770 Lufcy Nov. 13, 1956 Disclaimer 2,816,2GO.D0naZcZ G. Seargie, Pittsburgh, Pa. REGULATED DC. POWER SUPPLY. Patent dated Dec. 10, 1957. Disclaimer dated Feb. 20, 1963,

by the assignee, U m'ted States 0 f America as wepwesented by th Sewetary 0 f the [Va-11y Hereby enters this disclaimer to claims 1, 2, 3, 5 an [Oficz'al Gazette Apm'l (9, 1.963.]

d 6 of said patent.

Disclaimer 2,816,260.D0nald G. Georgie, Pittsburgh, Pa. REGULATED DC. POWER SUPPLY. Patent dated Dec. 10, 1957. Disclaimer dated Feb. 20, 1963, by the assignee, United States of America as e'e m'esented by the Sewetarg 0 f the 1V avy. Hereby enters this disclaimer to claims 1, *2, 3, 5 and 6 of said patent.

[Oyfiez'al Gazette April 9,1963] 

